1. Field of the Invention
This invention relates to surgical stapling apparatus, and more particularly to surgical apparatus to perform sequential operations such as tissue clamping, staple forming and/or tissue cutting.
2. Description of Related Art
Surgical stapling apparatus is known wherein tissue is first grasped or clamped between opposing jaw structure and then fastened by means of fasteners. In some instruments a knife is provided to cut tissue which has been joined. The fasteners are typically in the form of surgical staples; however, two part polymeric type fasteners are also known.
Instruments for this purpose can comprise two elongated fingers which are respectively used to capture or clamp tissue. Typically, one of the fingers carries a disposable cartridge housing a plurality of staples arranged in at least two lateral rows while the other finger comprises an anvil for curling the staple legs into hook form upon their being driven against the anvil. The stapling operation is effected by a cam bar which travels longitudinally along the cartridge carrying finger, acting on transversely mounted pushers which in turn act upon the staples to place rows of staples in body tissue. A knife may optionally be positioned to operate sequentially immediately behind the cam bar and laterally positioned between the staple rows to longitudinally cut and/or open the stapled tissue between the rows of staples. Such instruments are disclosed in U.S. Pat. No. 3,079,606 to Bobrov et al. and U.S. Pat. No. 3,490,675 to Green. The instruments disclosed therein comprise apparatus for simultaneously making a longitudinal incision and applying a row of staples on both sides of an incision.
A later development disclosed in U.S. Pat No. 3,499,591 to Green applies a double row of staples on each side of the incision. This is accomplished by a cartridge assembly wherein a cam member moves within a guide path between two sets of staggered staple carrying grooves. Staple drive members located within the grooves each have two staple pusher plates, and sloping surfaces disposed within the guide path so as to be contacted by the longitudinally moving cam and be driven along the groove to effect ejection of two staples.
The cartridge assemblies typically come in a plurality of sizes, each varying in wire diameter, staple size and number of staples contained therein. Depending on the procedure to be performed, the surgeon must select the appropriate cartridge assembly.
The instruments described above were all designed to be used in surgical procedures wherein surgeons have direct manual access to the operation site. However, in endoscopic or laparoscopic procedures surgery is performed through a small incision or through narrow cannulae inserted through small entrance wounds in the skin. In order to address the specific needs of endoscopic and/or laparoscopic surgical procedures, endoscopic surgical stapling apparatus such as that shown in U.S. Pat. No. 5,040,715 to Green et al. have been developed This apparatus is well suited for such procedures and incorporates a distal end having an anvil and staple cartridge assembly and a manually operated handle assembly interconnected by an endoscopic portion which permits the instrument to be inserted into a cannula and be remotely operated by the surgeon.
The instruments discussed above all require some degree of manually applied force in order to clamp, fasten and/or cut tissue. This manual application can prove awkward or difficult depending upon the orientation of the instrument relative to the surgeon, the type of tissue being operated on, the number of staples to be placed or the strength of the surgeon. Furthermore, cause of the difficulty and expense of cleaning and sterilizing surgical instruments between uses, there is increasing interest in and demand for instruments which are disposable after use in a single surgical procedure rather than permanent and reusable. And because of the greater convenience and ease of using self-powered instruments as well as the more uniform results typically produced by self-powered instruments (as compared especially to manually powered instruments), there is increasing interest in and demand for instruments which are self-powered.
Therefore, it is one object of the present invention to provide a self contained gas powered surgical apparatus for driving fasteners into body tissue.
It is a further object of the present invention to provide a self contained gas powered surgical apparatus insertable through a small incision or narrow tube for driving surgical fasteners into body tissue and cutting the body tissue between rows of staples.
Another object of the present invention is to provide a self contained gas powered surgical apparatus which is disposable after use.
A further object of the present invention is to provide a self contained gas powered surgical apparatus having a gas metering element to prevent firing of the staples from the cartridge unless a sufficient quantity of gas is available to move the driving member through a full sequence of operation.
Another object of the present invention is to provide a surgical apparatus having a clamping lockout mechanism which will prevent clamping of tissue unless the cartridge has been properly inserted in the instrument.
A further object of the present invention is to provide a self contained gas powered surgical apparatus having sealing structure for inhibiting the escape of gas through the apparatus.
Another object of the present invention is to provide a self contained gas powered surgical apparatus having counter structure for displaying the number of times the instrument may be fired.
A further object of the present invention is to provide a self contained gas powered surgical apparatus with lockout structure to disable the apparatus after a predetermined number of firings.
Another object of the present invention is to provide a self contained gas powered surgical apparatus having a unique counter mechanism which indicates the number of times the apparatus may be fi and which prevents firing of the apparatus after a predetermined number of firings.
A further object of the invention is to provide a surgical apparatus which disables an actuation mechanism in the absence of an unfired fastener cartridge.
Another object of the invention is to provide a surgical apparatus which will disable an incompatible fastener cartridge upon loading to prevent firing of the incompatible cartridge in the apparatus.